We’re in week 3 of this LED sign project, and we now know how to finish it up. We had previously soldered all the anodes on the LEDs, but we were a bit confused about the connections of the cathodes and resistors. As we had been working off of a MAKE video, which breezed over the connections, we realized we really weren’t entirely sure of how to make those final connections.
I got the needed resistors right before Christmas, though hadn’t had a chance to post this yet. As you can see, there’s a 270Ω resistor, a 9V battery, and a 10mm LED working… along with the resistors, I got a 9V power supply, so we can make signs and run them off the wall, rather than relying on a ton of batteries. As I’m unsure about just how long a whole bunch of LEDs could run on battery, I suppose depending on the size of the batteries this could vary… connecting a bunch of D batteries to add up to 9V will certainly last longer than one of these alone.
We’ll get started on this soon.